How this instrument works
Paper towels and electric hand dryers get their carbon footprint from very different places in their life cycle. A paper towel's footprint comes almost entirely from manufacturing — growing or recycling the pulp, processing it into sheets, and shipping the finished product — while an electric dryer's footprint comes almost entirely from the electricity it draws every time someone uses it, which depends heavily on how that electricity was generated.
The MIT Materials Systems Laboratory's 2011 life-cycle assessment of hand-drying systems put a virgin paper towel sheet at about 5.96 g CO2e and a recycled-content sheet at about 6.08 g CO2e — recycling doesn't necessarily reduce the footprint since reprocessing pulp has its own energy cost. This calculator uses that per-sheet figure directly, but computes the dryer's footprint from first principles — its wattage times how long each dry takes — rather than citing one fixed 'per dry' number, because that lets you plug in your own dryer's actual power rating and your own electricity grid's carbon intensity.
Grid carbon intensity varies enormously by location, from under 50 g CO2e per kWh in grids dominated by hydro or nuclear power to over 700 g CO2e per kWh in coal-heavy grids — which is exactly why this calculator exposes it as an adjustable input rather than baking in one number that would be wrong for most readers. The default of 400 g CO2e/kWh is a rough global-average placeholder, not a claim about any specific location.
- Enter Hand-dries per day and Days per year for your washroom's usage pattern.
- Enter Paper towel sheets used per dry and its CO2e per sheet (virgin or recycled).
- Enter your dryer's Power in watts and typical Seconds per dry.
- Adjust Grid carbon intensity to match your local electricity mix if you know it.
- Read the annual CO2e for each option and which one comes out ahead.
Worked example — a busy washroom, 100 dries a day
A washroom with 100 hand-dries a day, open 250 days a year, uses 2 virgin paper towel sheets per dry at 5.96 g CO2e each: 100 × 250 × 2 × 5.96 ÷ 1000 = 298 kg CO2e a year from paper towels alone.
An 1,800-watt warm-air dryer running for 30 seconds per dry uses 1,800 × 30 ÷ 3,600,000 = 0.015 kWh per dry. Over the same 25,000 dries a year, that's 375 kWh, which at a 400 g CO2e/kWh grid intensity comes to 375 × 400 ÷ 1000 = 150 kg CO2e a year — 148 kg less than the paper towels, meaning the dryer wins on this grid at these usage levels.
Questions
Which is really better for the environment, paper towels or hand dryers?
It depends heavily on your local electricity grid — the MIT 2011 life-cycle assessment this calculator draws its paper-towel figure from found electric dryers generally competitive with or better than paper towels on a clean grid, but a dryer running on electricity from a coal-heavy grid can lose that advantage entirely. That's exactly why this calculator makes grid carbon intensity an adjustable input rather than declaring one universal winner.
Does recycled paper towel have a lower footprint than virgin paper towel?
Not necessarily — the MIT study found recycled-content paper towel at about 6.08 g CO2e per sheet, very slightly higher than virgin paper towel's 5.96 g CO2e per sheet, because reprocessing recycled pulp carries its own energy cost that partly offsets the benefit of not harvesting new fibre. The two figures are close enough that sheet usage and dryer efficiency matter far more to the overall comparison than the virgin-versus-recycled choice alone.
Why does grid carbon intensity matter so much to the dryer's footprint?
Because essentially the entire footprint of an electric hand dryer, unlike a paper towel, comes from the electricity it consumes during use rather than from manufacturing the dryer itself — and how much CO2e that electricity represents depends entirely on how it was generated. A dryer plugged into a grid running mostly on hydro or nuclear power can have a tiny footprint, while the same dryer on a coal-dominated grid can have a much larger one, even though the dryer itself and its usage pattern haven't changed at all.
Does using fewer paper towel sheets per dry make a real difference?
Yes, proportionally — since the paper towel total scales directly with sheets used per dry, cutting from 2 sheets to 1 sheet per dry roughly halves the paper-towel side of the comparison. Many jet-air and high-speed dryers are specifically designed to dry hands faster than the equivalent paper-towel routine, which is part of why some newer dryer models report much lower footprints than the generic warm-air dryer this calculator's defaults represent.
Does this calculator include manufacturing the hand dryer unit itself?
No — it computes only the electricity used per dry, not the dryer's own manufacturing footprint, which is amortised over potentially tens of thousands of uses across the unit's working life and becomes a small contribution per dry compared with per-use electricity draw. The paper towel side similarly excludes packaging and dispenser manufacturing, keeping both sides focused on their dominant, per-use cost.